M2高速钢共晶碳化物形态与稳定性研究

Research on Morphologies and Stability of Eutectic Carbide in M2 High Speed Steel

采用不同尺寸模具浇注了M2高速钢,研究了冷却速度变化对其铸态组织特别是共晶碳化物形态、结构的影响规律。结果表明,当铸锭直径尺寸减小时,冷却速度加快,高速钢碳化物分布更均匀,M2C碳化物形态由片状变成纤维状。与片状碳化物相比,纤维状碳化物稳定性更低,加热时更容易分解,使碳化物明显球化、尺寸显著减小,提高了高速钢组织均匀性,有利于获得良好的硬度和韧性配合。

M2 high speed steel was cast with different size mould.The effect of cooling rate change on the microstructure of high speed steel,especially the morphology and structure of eutectic carbide was studied.The results show that when the diameter of the ingot is reduced,the cooling rate is accelerated,and the carbide distribution of high-speed steel is more uniform and the shape of M2C carbide changes from flake to fiber.Compared with flaky carbides,fibrous carbides are less stable and easier to decompose by heating,which makes carbides spheroidized and refine obviously,improve the microstructure uniformity of high-speed steel,and it is beneficial to obtain good hardness and toughness matching.